The most common and most likely answer to this crossword clue is the 11 letter word SWINGOMETER
I've seen this crossword clue in The Daily Telegraph
S
W
I
N
G
O
M
E
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R
More clues leading to the result SWINGOMETER
Buddy explains!
The straight part
We know that "it’s used during election" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’s used during election = swingometer.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SWINGOMETER mean?
SWINGOMETER noun- A graphic device used to illustrate swing in an election.